Solid arrows point from a parent (sub)module to the submodule which is descended from it. Dashed arrows point from a module being used to the module using it.
Solid arrows point from one derived type to another which extends (inherits from) it. Dashed arrows point from a derived type to another type containing it as a components, with a label listing the name(s) of said component(s).
Solid arrows point from a procedure to one which it calls. Dashed arrows point from an interface to procedures which implement that interface. This could include the module procedures in a generic interface or the implementation in a submodule of an interface in a parent module.
subroutine assert_print_count()
call print_footer('#================================================')
call print_summary('Executed '//object_string(counter)//' assertions.')
end subroutine assert_print_count